QT-通过Http进行下载操作

#include <QNetworkAccessManager> #include <QNetworkReply> #include <QNetworkRequest> #include <QMessageBox> #include <QFileDialog> #include <QFileInfo> #include <QDebug> #include "mainwindow.h" #include "ui_mainwindow.h" MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { ui->setupUi(this); setWindowTitle(QStringLiteral("HTTP下载工具")); ui->mainToolBar->hide(); m_pReply = nullptr; m_bytesTotal = 0; m_pManager = new QNetworkAccessManager(this); connect(ui->pushButton, SIGNAL(clicked()), this, SLOT(saveAsFile())); } MainWindow::~MainWindow() { if (m_pReply && m_pReply->isOpen()) { disconnect(m_pReply, SIGNAL(finished()), this, SLOT(onFinished())); m_pReply->close(); } if (m_file.isOpen()) { m_file.close(); } delete ui; } void MainWindow::saveAsFile() { m_url.setUrl(ui->lineEdit->text()); if (!m_url.isValid()) { QMessageBox::critical(this, QStringLiteral("错误"), QStringLiteral("文件路径错误！")); return; } QFileInfo info(ui->lineEdit->text()); QString fileName = QFileDialog::getSaveFileName(this, QStringLiteral("保存到"), ui->lineEdit->text(), info.suffix()); if (fileName.isEmpty()) { return; } m_file.setFileName(fileName); if (!m_file.open(QIODevice::WriteOnly)) { QMessageBox::critical(this, QStringLiteral("错误"), QStringLiteral("本地文件创建失败！")); return; } ui->progressBar->setValue(0); downLoad(); ui->pushButton->setEnabled(false); ui->lineEdit->setEnabled(false); } void MainWindow::readData() { m_file.write(m_pReply->readAll()); } void MainWindow::onDownloadProgress(qint64 bytesReceived, qint64 bytesTotal) { ui->progressBar->setMaximum(bytesTotal); ui->progressBar->setValue(bytesReceived); m_bytesTotal = bytesTotal; double total = (double)bytesTotal / (1024 * 1024); double bytes = (double)bytesReceived / (1024 * 1024); double speed = bytes / (m_time.elapsed() / 1000); ui->statusBar->showMessage(QStringLiteral("总大小:%2MB - 已下载 %1MB - 速度: %3 MB/s").arg(bytes).arg(total).arg(speed)); } void MainWindow::onFinished() { m_file.flush(); m_file.close(); m_pReply->deleteLater(); m_pReply = nullptr; ui->pushButton->setEnabled(true); ui->lineEdit->setEnabled(true); double total = (double)m_bytesTotal / (1024 * 1024); ui->statusBar->showMessage(QStringLiteral("总大小:%2MB - 已下载 %1MB - 速度: %3 MB/s").arg(total).arg(total).arg(0)); QMessageBox::information(this, QStringLiteral("提示"), QStringLiteral("下载完成！")); } void MainWindow::downLoad() { m_pReply = m_pManager->get(QNetworkRequest(m_url)); connect(m_pReply, SIGNAL(readyRead()), this, SLOT(readData())); connect(m_pReply, SIGNAL(downloadProgress(qint64, qint64)), this, SLOT(onDownloadProgress(qint64, qint64))); connect(m_pReply, SIGNAL(finished()), this, SLOT(onFinished())); m_time.start(); }